curl --request POST \
  --url https://api.bfl.ai/v1/flux-2-klein-4b \
  --header 'Content-Type: application/json' \
  --header 'x-key: <api-key>' \
  --data '
{
  "prompt": "ein fantastisches bild",
  "input_image": "<string>",
  "input_image_2": "<string>",
  "input_image_3": "<string>",
  "input_image_4": "<string>",
  "seed": 42,
  "width": 0,
  "height": 0,
  "safety_tolerance": 2,
  "output_format": "jpeg",
  "webhook_url": "<string>",
  "webhook_secret": "<string>"
}
'

{
  "id": "<string>",
  "polling_url": "<string>",
  "cost": 123,
  "input_mp": 123,
  "output_mp": 123
}